I'm making a large flag for our local theatre which will consist of a black lyre ( just over 1 metre high ) on a white background, which is the colour of the cotton fabric I'm using . I plan to make up a paste and paint on the dye. I'm not too worried if I don't get a sharp edge as the flag will not be seen close up.I'm not sure if I need to heat set this dye. According to Susan Druding (www.straw.com/sig/procion.html) I do. But according to www.pburch.net/dyeing/fiberreactive.shtml I don't.What is the correct recommended method?

The difference between the two recipes you reference is not only heat, but the fixative used in those methods. Paula recommends using sodium carbonate - Soda Ash - in which you would pre-soak the fabric. After applying the dye you would then cover or jellyroll wrap the fabric in plastic to maintain the moisture while the batching (fixing) process takes place over the next 12 -24 hours. Procion MX prefers a temperature in the range of 70 - 80 F to fix during the batching period.Susan recommends the use of baking soda (sodium bi-carbonate) mixed into the dye just before you use it. It would then be necessary to steam the piece in order to fix the dye as the baking soda doesn't create as low a ph environment and requires the additional assistance of moist heat to ensure proper fixing. Both methods are explained at our instruction page: Silk Screening and Handpainting.Hope this helps!

Thanks for clearing that up. It's so obvious now that you've pointed it out. If I use sodium bicarb can I just pop the fabric into the drier or does it also need some form of added moisture, ie a damp towel?If instead i go for soda-ash how do I stop the dye paste from drying out while I'm working. I will have a fairly large area to dye and the air temperature needs be warm.(30C) Can I spray the applied paste with water or would it be better to cover each completed area with cling wrap?Lastly does one method give better results (stronger colours) than the other?